On Wed, 2 Oct 2013 22:57:41 +0100 Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > No, that is a factor I had not considered. I had been concerned about > monitoring latency whilst minimising frequency and using the power gauge > as the ultimate measure of success. One thing that is apparent with ivb, > is that the power gauge (at least) is dependent upon workload. That is > you can set high frequencies, but if the ring is idle (but not in rc6) > then it consumes relatively little power. (That still may be 1W on the > big GPUs, but it does mean that at low frequencies there is not a lot of > difference between rc6 on/off, a few 10s of mW, and we are concerned > with a window of about 10ms.) I suspect the difference is likely to be > in the noise for an idle desktop workload and would only really show > itself in a synthetic benchmark. Hm are you sure about that? It doesn't match the last measurements I had from a long time ago... until RC6 kicked in the GPU burned quite a bit (several Watts). If you're correct though, then I agree, this is quibbling over crumbs, so not worth modifying. > So we want to race-to-idle, except for when we don't want to > race-to-idle. Seems like a good reason to keep improving our measuring > tools. Always. Jesse _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
